Speaker wiring/Ohm setting 410 65W

I recently purchased a MM 410 65w (My favorite MM so far). What was the original speaker wiring for this amp? It looks like the speakers are wired series/parallel with 4 8-ohm speakers. Is this common for MM? The total load (I think) is 8ohm. The previous owner told me to keep it set for 4-ohm (not sure why). What is the correct setting (I would say 8-ohm)? This site is awesome I have been playing out with these amps since the 70�s good to see there are other MM people out there.
Thanks,
Phil

You have it correct... a series string of two parallel pairs of 8-ohm drivers for a total impedance of 8 ohms.
The 8-ohm switch position should be the proper setting for a standard speaker load-out and wiring. Does it WORK at that setting? Maybe the previous owner had a switch problem or a wiring problem and the amp didn't work well in that position? The wrong setting probably won't kill the amp (you may like the sound too!), but the intended position is 8-ohms.
When in doubt, unplug the speaker cable (amp power off) and measure between the Tip & Ring of the phone plug with an ohmmeter. You should read somewhere around 6 ohms of resistance in a typical 8-ohm load.
Steve